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Slow file access over DFS in branch office when WAN link is down RRS feed

  • Question

  • Hi,

    we have 3 DCs in our main office and one RODC in a branch office. Additionally we have a file server cluster in our main office and the data are synchronized via DFS to a file server in the branch office. Access to the files is also managed by DFS.

    The namespaceservers for the namespace are the cluster servers and the file server in the branch office.

    The targets for the folders are the shares on the cluster and the shares on the file server in the branch office.

    Synchronization works fine but when the connection to the main office is lost the access to the DFS shares is extremely slow. It works but you have to wait about 20-30 seconds before a folder opens. Also opening documents and files is very slow. Once a folder was opened the access times are ok.

    When the users access the files by using the UNC path to the file server in the branch office instead of using the DFS path the performance is very good.

    \\fileserver\share1 works fine.

    \\domain.local\branch\share1 is very slow.

    Target Priority to Override Referral Ordering is set to the targets on the file server of the branch office.

    nslookup domain.local shows a 2 second time out and than lists the three domain controllers as result without the RODC.

    As I have read this is normal and wanted but is it possible that this is the reason for the slow access times in connection with DFS?

    All systems are based on Server 2008 R2 with all actual updates.

    Has someone an idea what's the reason fo rthe slow response times?

    Regards

    Markus




    Thursday, July 5, 2012 9:33 AM

Answers

  • Hi Markus,

    I think it is because that when client trying to access a Domain based DFS namespace, it will first trying to connect DC. As the connection to main office is down, it will cause the delay before it get a correct DFS namespace server.

    For detailed information you could find in this thread:

    How DFS works

    http://technet.microsoft.com/en-us/library/cc782417(v=ws.10)


    TechNet Subscriber Support in forum |If you have any feedback on our support, please contact tnmff@microsoft.com.

    Friday, July 6, 2012 9:25 AM

All replies

  • Hi Markus,

    I think it is because that when client trying to access a Domain based DFS namespace, it will first trying to connect DC. As the connection to main office is down, it will cause the delay before it get a correct DFS namespace server.

    For detailed information you could find in this thread:

    How DFS works

    http://technet.microsoft.com/en-us/library/cc782417(v=ws.10)


    TechNet Subscriber Support in forum |If you have any feedback on our support, please contact tnmff@microsoft.com.

    Friday, July 6, 2012 9:25 AM
  • Hi Shaon,

    thanks for your answer.

    I thought this would be the job of the RODC in the branch office because the DFS data is replicated to all domain controllers.

    Friday, July 6, 2012 9:38 AM